Men who paint for a living may be placing their unborn children at increased risk of birth defects and low birth weight.

A study of construction workers in the Netherlands, conducted in part by the University of Alberta in Edmonton, Canada, links low birth weight and birth defects to paternal, airborne exposure to organic solvents such as paints, thinner and cleansers.

The study, although preliminary in its parent-reported assessment of birth outcomes and small numbers of reported cases, is the first of its kind to link concentrations of solvents in the air to these health outcomes, said Dr. Igor Burstyn, a University of Alberta professor of occupational and environmental health, who co-authored the study with researchers from Radboud University Nijmegen Medical Centre in the Netherlands. "This is the first time we have good exposure data in such a study, but more robust investigations are needed to guide policy-makers," Dr. Burstyn said.

The study focused on questionnaires filled out by a random sample of 398 painters exposed to a mixture of chemicals present in organic solvents and 302 carpenters with little or no exposure, in the period of three months before the last pregnancy. Workers employed as painters three months before their partners became pregnant were on average six times more likely than the carpenters to father congenitally malformed babies (e.g. defects of cardiovascular, gastrointestinal, urogenital and central nervous systems.)

In addition, the painters exposed to the chemicals were 50 to 100 per cent more likely to produce low birth-weight babies, depending on the level of exposure, compared to unexposed carpenters.

The researchers are unsure of how the chemicals are contributing to birth defects, and previous studies are inconclusive.

Of particular concern, said Dr. Burstyn, is that all of the levels of exposure to solvents investigated in the study were well within Dutch regulations and occupational exposure limits established in the United States and Canada. Therefore, they had previously been considered safe. "Now it is less certain whether these exposures are safe," Dr. Burstyn said.

The findings show a need for more research, especially among workers who are exposed to supposedly less harmful water-based paints that were introduced to replace traditional solvent-based paints formerly common in the Netherlands. "We need to evaluate and compare the influence of resulting solvent exposures on reproductive health," said Dr. Burstyn, who collaborated previously on a study showing that water-based paints did not eliminate solvent exposure among construction painters.

Organic solvents are widely used in many industries including plastics, metals, electronics, shoemaking, furniture manufacturing, painting, printing and dry cleaning.